the faa says carriers must prove the batteries are safe before flights can resume. >>> an investigation is underway into a possible outbreak of the norovirus at a contra costa elementary school. paul chambers is live in la fayette where the campus just got a thorough cleaning. good afternoon, paul. >> reporter: good afternoon, tori. public health officials spent the afternoon and morning here at the elementary school taking samples from students to check to see if this is indeed a norovirus outbreak. it's been a tough week for students and staff in la fayette e the principal says last thursday, some students and faculty started to get sick. by the next day, more than 100 of the 750 students were absent, claiming they had symptoms similar to the norovirus. >> it looks like norovirus based on the illness and the length of time one becomes ill. >> reporter: although think it's the stomach flu, it's not related to influenza. >> it does affect your stomach, causing the nausea, diarrhea, vomiting. >> reporter: cleaning crews spent their weekend scrubbing classrooms and working with public hea